diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2025-10-27 09:44:33 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-11-04 08:30:50 +0100 |
| commit | faba9d250eaec7afa248bba71531a08ccc497aab (patch) | |
| tree | 2c178787b061b036b397b6a02379499964595288 /include/linux/sched.h | |
| parent | 566d8015f7eef11d82cd63dc4e1f620fcfc2a394 (diff) | |
rseq: Introduce struct rseq_data
In preparation for a major rewrite of this code, provide a data structure
for rseq management.
Put all the rseq related data into it (except for the debug part), which
allows to simplify fork/execve by using memset() and memcpy() instead of
adding new fields to initialize over and over.
Create a storage struct for event management as well and put the
sched_switch event and a indicator for RSEQ on a task into it as a
start. That uses a union, which allows to mask and clear the whole lot
efficiently.
The indicators are explicitly not a bit field. Bit fields generate abysmal
code.
The boolean members are defined as u8 as that actually guarantees that it
fits. There seem to be strange architecture ABIs which need more than 8
bits for a boolean.
The has_rseq member is redundant vs. task::rseq, but it turns out that
boolean operations and quick checks on the union generate better code than
fiddling with separate entities and data types.
This struct will be extended over time to carry more information.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084306.527086690@linutronix.de
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 14 |
1 files changed, 3 insertions, 11 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 6627c527c2c7..15627769409d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -41,6 +41,7 @@ #include <linux/task_io_accounting.h> #include <linux/posix-timers_types.h> #include <linux/restart_block.h> +#include <linux/rseq_types.h> #include <uapi/linux/rseq.h> #include <linux/seqlock_types.h> #include <linux/kcsan.h> @@ -1406,16 +1407,8 @@ struct task_struct { unsigned long numa_pages_migrated; #endif /* CONFIG_NUMA_BALANCING */ -#ifdef CONFIG_RSEQ - struct rseq __user *rseq; - u32 rseq_len; - u32 rseq_sig; - /* - * RmW on rseq_event_pending must be performed atomically - * with respect to preemption. - */ - bool rseq_event_pending; -# ifdef CONFIG_DEBUG_RSEQ + struct rseq_data rseq; +#ifdef CONFIG_DEBUG_RSEQ /* * This is a place holder to save a copy of the rseq fields for * validation of read-only fields. The struct rseq has a @@ -1423,7 +1416,6 @@ struct task_struct { * directly. Reserve a size large enough for the known fields. */ char rseq_fields[sizeof(struct rseq)]; -# endif #endif #ifdef CONFIG_SCHED_MM_CID |